1. Field of the Invention
This invention relates to a payment transaction method and a payment transaction system. In particular, the present invention relates to a payment transaction method as set forth in the preamble of the independent method claim 1 and a payment transaction system for execution of this payment transaction method.
2. Discussion of the Background
Owing to the increasing popularity and spread of mobile telephony, more and more customers of service points, so-called points of sale (POS), for example points of sale of products and/or services, are equipped with portable mobile telephones, in particular mobile radio telephones, which support the identification and authentication of a respective customer. Since non-cash forms of payment are being used more and more frequently for paying for products and/or services at the service point, and the customers are provided with numerous different identification cards for this purpose from the various service points, there has been a desire to use the above-mentioned portable mobile devices for this purpose. Conventional mobile radio telephones comprise an identification module, a so-called SIM (Subscriber Identification Module) chipcard, which contains a clear user identification, for example an IMSI (International Mobile Subscriber Identity), by means of which the respective user can be identified in a telecommunications network. To prevent the use of such a mobile device by an unauthorized user, a user must first authenticate himself at the mobile device, for example by entering a personal code (Personal Identification Number, PIN) by means of operating elements of the mobile device, which code, with the aid of security services, is compared with a value stored on the SIM chipcard.
Described in the patent application EP 708 547 A2 is the use of a mobile radio telephone as the authenticated transaction controller. According to the teaching disclosed in EP 708 547 A2, a customer first authenticates himself in a sales store at his mobile radio telephone, for example through entry of a personal identification code; afterwards the store operator and the customer agree upon a transaction password, which is entered in his mobile radio telephone by the customer, and is transmitted wirelessly, together with identification data, for example the appliance number and the telephone number of the mobile radio telephone, to a receiver of a payment terminal of the sales store. According to the teaching disclosed in EP 708 547 A2, the respective amount to be paid, which is either supplied by the payment terminal or is entered by the customer in his mobile radio telephone and is transmitted together with the transaction password and the identification data to the receiver of the payment terminal, and the identification data are passed on by the sales store to a credit center for credit checking. The transaction password described in EP 708 547 A2 makes it possible in particular for the payment terminal to assign the data on the respective transaction transmitted from the mobile radio telephone, and thereby not be interfered with through possible transmissions from other mobile radio telephones.